Water-dilutable polyesters with cyclic imide structure

ABSTRACT

The present invention relates to novel polyesterpolyols with cyclic imide structure and to their use in coating compositions.

[0001] The present invention relates to novel water-dilutablepolyesterpolyols with cyclic imide structure and to their use in coatingcompositions.

[0002] From the prior art it is known that polyisocyanates containingfree isocyanate groups and having certain selected properties, such as,for example, viscosity or hydro-philicity, can be used in combinationwith different hydroxy-functional binders, examples being polyesters,polyacrylates or polyurethanes, in aqueous medium as crosslinkers undervarious conditions. Such systems are known, for example, from EP-A 0 358979, EP-A 0 469 389, EP-A 0 496 205, EP-A 0 537 568, EP-A 0 583 728,EP-A 0 654 053 and DE-A 41 35 571.

[0003] Also known from the prior art are aqueous clearcoat materialsbased on special acrylate dispersions and amino resins, in combinationwhere appropriate with blocked polyisocyanates. Examples thereof aredisclosed in EP-A 0 365 775, EP-A 0 363 723, EP-A 0 521 926 and EP-A 0521 927. The coating materials recited therein are unsuitable, however,for low baking temperatures. In particular, they cannot be processed onparts made of plastic.

[0004] DE-A 195 38 061 describes water-dilutable polyesters with narrowcompositional relationships, comprising both aromatic and cycloaliphaticbuilding blocks containing acid groups. The polyesters described areused preferably in automotive clearcoat materials for automotive OEMfinishing. A disadvantage with these polyesters is the inadequateresistance to hydrolysis.

[0005] Polymers with cyclic imide structures, e.g. polyamideimides fromdiamines and/or diisocyanates, tricarboxylic anhydrides andε-caprolactam, are frequently used for heat-resistant coatings in wireenamelling, as disclosed in DE-A 38 17 614 or DE-A 33 32 031. Alsodescribed are combinations with modified polyesters, for example in DE-A32 13 257. These polymers, however, are not water-dilutable.

[0006] The object of the present invention was to provide novelpolyesters suitable for preparing hydrolysis-resistant polyesterdispersions or polyester solutions which are aqueous or can be dilutedin water. The polyester dispersions ought additionally to be able to beused for preparing high-grade aqueous two-component polyurethane coatingmaterials and ought to meet the requirements imposed on the propertiesof the coating, for example drying, surface quality such as hardness,gloss, levelling, smoothness, fullness and effect, polishability andresistance to water, chemical agents or atmospheric effects, weatheringand mechanical influences. Moreover, the polyesters of the inventionought also to possess an elasticity such that they are suitable forcoating substrates made of plastic.

[0007] This object has been achieved through the provision of polyesterswith cyclic imide structure.

[0008] The invention accordingly provides polyesterpolyols

[0009] which comprise structural units of the general formula (I)

[0010] and/or which comprise structural units of the general formula(II)

[0011] Likewise provided by the present invention are polyesterpolyolswhich, as end groups,

[0012] comprise structural units of the general formula (III)

[0013] and/or comprise structural units of the general formula (IV)

[0014] in which

[0015] R¹ and R², independently of one another, are identical ordifferent and

[0016] stand for hydrogen, halogen, unsubstituted or substituted C₁-C₁₈alkyl, C₂-C₁₈ alkenyl, C₂-C₁₈ alkynyl, C₃-C₁₂ cycloalkyl, C₃-C₁₂hetero-cycloalkyl, C₆-C₂₄ aryl, C₁-C₁₈ alkoxy, C₁-C₁₈ alkylthio, C₁-C18alkyl-amino radicals or

[0017] with the joining carbon atom of the C₄N five-membered ring form aC₃-C₁₂ cycloalkyl or C₂-C₁₃ heterocycloalkyl radical optionallycontaining oxygen, nitrogen and/or sulphur or

[0018] both together with the joining carbon atoms of the C₄Nfive-membered ring form a fused cyclic or polycyclic ring system whichis saturated, unsaturated, partly or fully aromatic, is optionallysubstituted and optionally contains oxygen, nitrogen and/or sulphur.

[0019] The polyesterpolyols of the invention of the general formula (I),(II), (III) and (IV) contain free hydroxyl and carboxyl groups.

[0020] The polyesterpolyols of the invention have hydroxyl numbers offrom 10 to 400 mg KOH/g, preferably from 15 to 350 mg KOH/g and morepreferably from 20 to 300 mg KOH/g, acid numbers of from 5 to 100 mgKOH/g, preferably from 10 to 80 mg KOH/g and more preferably from 20 to60 mg KOH/g.

[0021] Suitable synthesis components for the polyesters of the inventionare acid components (A), cyclic lactams (B) and alcohol components (C).

[0022] Examples of suitable acid components are difunctional carboxylicacids or their derivatives (A1) such as aliphatic, cycloaliphatic oraromatic difunctional carboxylic acids or their anhydrides. Aliphaticdifunctional carboxylic acids are, for example, aliphatic saturateddicarboxylic acids such as oxalic acid, malonic acid, dimeth-ylmalonicacid, succinic acid, adipic acid, glutaric acid, azelaic acid, pimelicacid, suberic acid, sebacic acid or the possible anhydrides of theseacids and also unsaturated dicarboxylic acids such as fumaric acid,maleic acid, itaconic acid, citric acid or the possible anhydrides ofthese acids, for example. Preference is given to adipic acid and maleicanhydride. Cycloaliphatic difunctional carboxylic acids are, forexample, cyclopentanedicarboxylic acid, 1,3-,1,4-cyclohexanedicarboxylic acid, 2,5-norbomenedicarboxylic acid,endoethylenecyclohexanedicarboxylic acid and methyltetrahydrophthalicacid, tetrahydrophthalic acid, hexahydrophthalic acid or the possibleanhydrides of these acids. Preference is given to1,4-cyclohexane-dicarboxylic acid, tetrahydrophthalic anhydride andhexahydrophthalic anhydride. Examples of suitable aromatic difunctionalcarboxylic acids are terephthalic acid, isophthalic acid, phthalic acid,naphthalenedicarboxylic acid, biphenyldicarboxylic acid or the possibleanhydrides of these acids, preference being given to phthalicanhydrides, isophthalic acid and terephthalic acid. It is likewisepossible to use mixtures of the acids and anhydrides mentioned ascomponent (A1).

[0023] Likewise suitable as acid component are carboxylic acids having afunctionality of more than 2 (A2), such as trimellitic acid or trimesicacid (functionality=3, (A2′)) or pyromellitic acid orbenzophenonetetracarboxylic acid (functionality=4, (A2″)) or thepossible anhydrides of these acids. It is likewise possible to usemixtures of the acids and anhydrides mentioned as component (A2).

[0024] Suitable monocarboxylic acids (A3) are selected from the group ofthe aliphatic, cycloaliphatic or aromatic, saturated or unsaturated,monocarboxylic acid having 1 to 18 carbon atoms, preferably 1 to 12 andmore preferably 1 to 8 carbon atoms, such as formic acid, acetic acid,propionic acid, butyric acid, isobutyric acid, valeric acid,2-methylbutanoic acid, 3-methylbutanoic acid, 2,2-dimethylpropanoicacid, 2-ethylbutanoic acid, 2-ethylhexanoic acid, octanoic acid,decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid,octadecanoic acid, saturated and unsaturated fatty acids,cyclohexanecarboxylic acid, cyclohexenoic acid and benzoic acid or theanhydrides of these acids. It is likewise possible to use mixtures ofthese acids as component (A3). Preference is given to 2-ethylhexanoicacid, saturated and/or unsaturated fatty acids, cyclohexanoic acid andbenzoic acid.

[0025] Cyclic lactams (B) are compounds of the general formula (V) where

[0026] n stands for an integer from 3 to 5.

[0027] Examples of suitable compounds of component (B) areγ-butyrolactam and ε-caprolactam, preference being given toε-caprolactam.

[0028] Suitable alcohol components (C) include the following:

[0029] (C1) aliphatic or cycloaliphatic C₃-C₁₀ polyols having afunctionality of more than 2,

[0030] (C2) aliphatic or cycloaliphatic C₂-C₁₈ diols,

[0031] (C3) aliphatic, cycloaliphatic or araliphatic monofunctionalC₁-C₁₈ alcohols.

[0032] Component (C1) comprises aliphatic or cycloaliphatic C₃-C₁₀polyols having a functionality of more than 2, such as glycerol,trimethylolethane, trimethylolpropane, pentaerythritol,dipentaerythritol, sorbitol, reaction products of these polyols withε-caprolactone or alkylene oxides. Preference is given to C₃-C₈ polyols,such as glycerol, trimethylolpropane and pentaerythritol. It is alsopossible to use mixtures of the said polyols as component (C 1).

[0033] Component (C2) comprises aliphatic or cycloaliphatic C₂-C18diols, alcohols optionally containing ether oxygen atoms, such asethylene glycol, diethylene glycol, triethylene glycol, neopentylglycol,propane-1,2-diol and 1,3-diol, dipropylene glycol, butane-1,2-diol,-1,3-diol, -2,3-diol and -1,4-diol, pentane-1,5-diol,2,2-diethylpropanediol, hexane-1,6-diol and -2,5-diol,2-methyl-2,4-pentanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl- 1,5-pentane-diol,2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol,cyclohexane-1,4-dimethanol, cyclohexane-1,2-, -1,3- and -1,4-diol,2,2-bis(4-hydroxycyclo-hexyl)propane andoctahydro-4,7-methano-1H-indenedimethanol or reaction products of thesediols with ε-caprolactone or alkylene oxides. Preference is given tousing C₂-C₁₂ diols. Mixtures of such diols can likewise be used ascomponent (C2). Preference is given to ethylene glycol, diethyleneglycol, propane-1,2-diol, neopentylglycol, hexane-1,6-diol andcyclohexane-1,4-dimethanol.

[0034] Suitable compounds for component (C3) are aliphatic,cycloaliphatic or araliphatic monofunctional C₁-C₁₈ alcohols, such asmethanol, ethanol, 1- and 2-propanol, 1- and 2-butanol, isobutanol,tert-butanol, 1-, 2- and 3-pentanol, 2-methyl-1-butanol,3-methyl-1-butanol, 2,2-dimethylpropanol, 1-, 2- and 3-hexanol,4-methyl-2-pentanol, 2-ethyl-1-butanol, 2,2-dimethylpropanol, 1-octanol,2-ethyl-1-hexanol 1-nonanol, trimethyl-1-hexanol, 1-decanol,1-dodecanol, 1-tetradecanol, 1-hexa-decanol, 1-octadecanol,cyclohexanol, 2-, 3- and 4-methyl-cyclohexanol,hydroxy-methylcyclohexane, 3,3,5-trimethylcyclohexanol,4-tert-butylcyclohexanol, benzyl alcohol,1-methyl-4t-isopropylcyclohexanol=(−)-menthol, decahydro-2-naphthol,(1R-endo)- 1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol,(1R-exo)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol and(1R)-6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-methanol or reactionproducts of these monoalcohols with ε-caprolactone or alkylene oxides.Preference is given to C₁-C₁₂ alcohols, such as 1- and 2-butanol,isobutanol, 2-ethyl-1-hexanol, 1-nonanol, 1-decanol, 1-dodecanol,cyclohexanol, 3,3,5,-trimethyl-cyclohexanol, 4-tert-butylcyclohexanol,benzyl alcohol. Particular preference is given to C₁-C₁₀ alcohols, suchas 2-ethyl-1-hexanol, cyclohexanol, 3,3,5,-tri-methylcyclohexanol,4-tert-butylcyclohexanol and benzyl alcohol. Mixtures of suchmonoalcohols can likewise be used as component (C3).

[0035] The invention likewise provides a process for preparing thepolyesterpolyols of the invention comprising structural units of thegeneral formula (I) and/or (II) by

[0036] (I) reacting an anhydride of trimellitic acid and/or ofpyromellitic acid with a cyclic lactarn (B),

[0037] (II) synthesizing a hydroxy-functional polyester by adding analcohol component (C) containing

[0038] one or more aliphatic or cycloaliphatic C₃-C₁₀ polyols having afunctionality of more than 2 (C1) and/or

[0039] one or more aliphatic or cycloaliphatic C₂-C₁₈ diols (C2) and

[0040] optionally one or more aliphatic, cycloaliphatic or araliphaticmonofunctional C₁-C₁₈ alcohols (C3),

[0041] and also optionally adding an acid component (A) comprising

[0042] one or more difunctional carboxylic acids or their anhydrides(A1) and/or

[0043] one or more polyfunctional carboxylic acids or their anhydrides(A2) and

[0044] optionally one or more monocarboxylic acids (A3).

[0045] The invention likewise provides a process for preparing thepolyesterpolyols of the invention comprising structural units of thegeneral formula (III) and/or (IV) by

[0046] (I) reacting an anhydride of a difunctional carboxylic acids (A1)with a cyclic lactam (B),

[0047] (II) synthesizing a hydroxy-functional polyester by adding analcohol component (C) containing

[0048] one or more aliphatic or cycloaliphatic C₃-C₁₀ polyols having afunctionality of more than 2 (C1) and/or

[0049] one or more aliphatic or cycloaliphatic C₂-C₁₈ diols (C2) and

[0050] optionally one or more aliphatic, cycloaliphatic or araliphaticmonofunctional C₁-C₁₈ alcohols (C3),

[0051] and also optionally by adding an acid component (A) comprising

[0052] one or more difunctional carboxylic acids or their anhydrides(A1) and/or

[0053] one or more polyfunctional carboxylic acids or their anhydrides(A2) and

[0054] optionally one or more monocarboxylic acids (A3).

[0055] A general overview of the (preparative) preparation ofpolyesterpolyols and of the reaction conditions is given for example in“Ullmanns Encyclopädie der Technischen Chemie”, Verlag Chemie Weinheim,4th edition (1980) volume 19, pages 61 ff. or by H. Wagner and H. F.Sarx in “Lackkunstharze”, Carl Hanser Verlag, Munich (1971), pages 86 to152.

[0056] The polyesterpolyols of the invention can be processed both tosolvent-containing binders or solutions and to aqueous binders oraqueous solutions or dispersions. To prepare aqueous dispersions of thepolyesters of the invention the free carboxyl groups are neutralizedwith a neutralizing agent.

[0057] In one preferred embodiment of the process of the invention acidanhydride and lactam, optionally in the presence of alcohols (C)selected from group (C1) to (C3), are reacted with one another in afirst stage, giving structural units containing cyclic imide groups.This is followed in a second stage by the esterification with theremaining polyester building blocks, such as acid components (A) andalcohol components (C). The acid components (A1) are preferably used asacid component (A) for synthesizing the polyester. The process of theinvention is preferably conducted in the melt, optionally in thepresence of a catalytic amount of a usual esterification catalyst, suchas acids, bases or transition metal compounds, for example, such astitanium tetrabutoxide, dibutyltin oxide or butylstannic acid, forexample, at temperatures from 80 to 270° C., preferably from 100 to 260°C. Optionally it is also possible to add an azeotrope former, such asxylene, to discharge the water of reaction. The esterification reactionis carried out until the target values for the hydroxyl number and acidnumber and also for the viscosity have been reached. Preferably, in athird stage, the hydroxy-functional polyester is reacted with acarboxylic anhydride selected from the group of the difunctionalcarboxylic acids (A1) and/or trifunctional carboxylic acids (A2′), withring opening and half-ester formation.

[0058] It is likewise possible in principle to react all of thecomponents in one step to give the polyesters of the invention.

[0059] The carboxyl groups formed in the polyesterpolyols of theinvention may optionally be neutralized with a neutralizing agent,completely, partially or over-neutralized, so that the polyester becomeswater-dilutable. In that case the neutralizing agent can be addedbefore, during or after the ester of the invention is transferred to theaqueous phase.

[0060] The invention further provides aqueous solutions or dispersionswhich comprise the polyesterpolyols of the invention.

[0061] To prepare the polyester dispersion either the polyesterpolyol ofthe invention, where appropriate with strong shearing, such as vigorousstirring, for example, is introduced into the water or, conversely,water is stirred into the polyesterpolyol. The dispersing medium may atthe same time contain the neutralizing agent and/or further additives aswell.

[0062] Suitable neutralizing agents (D) include not only inorganic butalso organic bases. Preference is given to using primary, secondary andtertiary amines, such as ammonia, ethylamine, propylamine,dimethylamine, dibutylamine, cyclohexylamine, benzylamine, morpholine,piperidine, diethanolamine and triethanolamine. It is preferred to usetertiary amines, such as triethylamine, N,N-dimethylethanolamine,N,N-diethylethanolamine, triethanolamine, triisopropylamine,N-methylmorpholine, 2-amino-2-methylpropanol. Particular preference isgiven to N,N-dimethylethanolamine, triethanolamine and triethylamine.

[0063] The neutralizing agents (D) are normally used in amounts of from0.4 to 1.3 mol, preferably from 0.5 to 1.2 mol and more preferably from0.6 to 1.1 mol, relative to each mole of free carboxyl groups in thepolyester.

[0064] It is also possible to dissolve the polyesterpolyols of theinvention in an organic solvent after the second or third reaction stageand to use the polyester solution for preparing solvent-containingbinder.

[0065] Organic solutions of the polyesterpolyols of the invention aretherefore further provided by the invention.

[0066] Examples of suitable solvents are esters, such as ethyl acetate,butyl acetate, methoxypropyl acetate, methylglycol acetate, ethylglycolacetate, diethylene glycol monomethyl ether acetate; ketones, such asmethyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone;aromatics, such as toluene and xylene, and also the relativelyhigh-boiling hydrocarbon mixtures that are common in paint chemistry.

[0067] From the polyesterpolyols of the invention and/or their solutionsor dispersions it is possible to prepare binders for two-component (2K)polyurethane coating materials. In the case of blocked polyisocyanatesand/or amino resins, e.g. melamine resins, it is likewise possible touse the polyesterpolyols of the invention or their solutions ordispersions in one-component (1K) coating materials. Preference is givento their use as 2K polyurethane coating material.

[0068] As polyisocyanate component it is possible to use non-blocked orblocked polyisocyanates which are obtainable by modifying simplealiphatic, cycloaliphatic, araliphatic and/or aromatic diisocyanates,polyisocyanates synthesized from at least two diisocyanates and having auretdione, isocyanurate, allophanate, biuret, iminooxadiazinedioneand/or oxadiazinetrione structure, as described exemplarily for examplein J. Prakt. Chem. 336 (1994) page 185-200.

[0069] Suitable diisocyanates for preparing the polyisocyanates arediisocyanates which are obtainable by phosgenation or by phosgene-freeprocesses, for example by thermal urethane cleavage, and which come fromthe molecular weight range from 140 to 400 and contain aliphatically,cycloaliphatically, araliphatically and/or aromatically attachedisocyanate groups, such as, for example, 1,4-diisocyanatobutane,1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane,1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- and/or2,4,4-trimethyl-1,6-diisocyanatohexane 1,10-diisocyanatodecane, 1,3- and1,4-diisocyanatocyclohexane, 1,3- and1,4-bis(isocyanatomethyl)cyclohexane,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate, IPDI), 4,4′-diisocyanatodicyclohexylmethane,1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane,bis(isocyanatomethyl)-norbornane, 1,3- and1,4-bis(2-isocyanatoprop-2-yl)benzene (TMXDI), 2,4- and2,6-diisocyanatotoluene (TDI), 2,4′- and4,4′-diisocyanatodiphenylmethane, 1,5-diisocyanatonaphthalene or anydesired mixtures of such diisocyanates.

[0070] Moreover, triisocyanates such as triphenylmethane4,4′,4″-triisocyanate and/or 4-isocyanatomethyloctane 1,8-diisocyanateare also suitable.

[0071] It is preferred to use polyisocyanates or polyisocyanate mixturesof the type mentioned containing exclusively aliphatically and/orcycloaliphatically attached isocyanate groups.

[0072] Particularly preferred polyisocyanates or polyisocyanate mixturesare those with isocyanurate and/or biuret structure based on HDI, IPDIand/or 4,4′-diisocyanatodicyclohexylmethane.

[0073] In order to achieve better incorporability of the saidpolyisocyanates into aqueous binders, the polyisocyanates are preferablyhydrophilically modified. Use is made for this purpose, by methods whichare known per se, of polyisocyanates of the abovementioned type. Thehydrophilicization can take place, for example, anionically,cationically or nonionically, by way of internal or externalemulsifiers.

[0074] Polyisocyanates hydrophilicized by internal emulsifiers are, forexample, those which have been hydrophilicized by carboxyl groups andwhich, following neutralization of the carboxyl groups, can be stirredwith very fine division into aqueous systems without the need for highshearing forces. Such polyisocyanates are, for example, subject-matterof EP-A 443 138 and EP-A 510 438. It is additionally possible to usepolyisocyanates hydrophilically modified by polyethers. The preparationof such water-dispersible polyisocyanates containing urethane groupsare, for example, subject-matter of EP-A 206 059, EP-A 540 985 and ofU.S. Pat. No. 5,200,489. Water-dispersible polyisocyanates which containallophanate groups and have been hydrophilically modified withpolyethers, and their preparation, are subject-matter of EP-A 0 959 087.2K PU coating materials based on these polyisocyanates aresubject-matter of EP-A 959 115 and of EP-A 1 065 228.

[0075] Likewise suitable are the water-emulsifiable polyisocyanatesdescribed in EP-A 0 703 255, comprising as ionic emulsifiers reactionproducts of polyisocyanates and any desired hydroxy-, mercapto- oramino-functional compounds having at least one sulphur-acidic group oranion thereof. Preferred sulphur-acidic synthesis components specifiedthere for preparing the emulsifiers are hydroxysulphonic acidscontaining aliphatically attached OH groups or the salts of suchhydroxysulphonic acids, examples being special polyethersulphonates, astraded, for example, under the name Tegomer® (Th. Goldschmidt AG, Essen,DE), bisulphite adducts with unsaturated alcohols,hydroxyethanesulphonic and hydroxypropanesulphonic acid, andamino-sulphobetaines preparable by quaternizing tertiary amino alcoholswith 1,3-propane sultone. Also preferred are2-(cyclohexylamino)ethanesulphonic acid and3-(cyclohexylamino)propanesulphonic acid or salts thereof ashydrophilicizing components.

[0076] Examples of suitable external emulsifiers are anionicemulsifiers, such as those based on alkyl sulphate,alkylarylsulphonates, alkylphenol polyether sulphates as indicated forexample in Houben-Weyl, Methoden der organischen Chemie, additional andsupplementary volumes, 4^(th) Edition, Volume E20, 1987 (Part 1, pages259 to 262) or alkyl polyether sulphates, or nonionic emulsifiers, suchas the alkoxylation products, preferably ethoxylation products, ofalkanols, phenols or fatty acids.

[0077] The polyisocyanates have an NCO content of I to 45% by weight,preferably from 8 to 25% by weight. They may optionally be diluted witha solvent which is at least partly miscible with water but is inerttowards isocyanate groups.

[0078] Preference is given to using polyisocyanates which containurethane groups and are hydrophilicized by internal emulsifiers, whichare subject-matter of EP-A 540 985, for example, and polyisocyanatescontaining allophanate groups, which are described, for example, in EP-A0 959 087. Particular preference is given to using polyether-modifiedpolyisocyanates containing allophanate groups, disclosed in EP-A 0 959087. Preferably 60 to 99 mol % of the polyether are attached to thepolyisocyanate by way of allophanate groups.

[0079] The present invention also provides a process for preparingsolvent-containing or aqueous coating compositions, characterized inthat the polyisocyanate component and optionally further binders areincorporated by stirring or emulsification into the binder comprisingthe polyesterpolyols of the invention.

[0080] The quantitative ratio of binder component and curing componentin this case is chosen such that for each hydroxyl group of the resincomponent there are from 0.1 to 3.0, preferably from 0.5 to 2.0 and morepreferably from 0.7 to 1.7 isocyanate groups of the curing component.

[0081] Prior to the addition of the curing component it is possible toincorporate the customary auxiliaries and additives of coatingstechnology into the binder component or the curing component, butpreferably the binder component. These include, for example, defoamers,thickeners, levelling agents, pigments, fillers, emulsifiers, dispersingassistants, light stabilizers and also solvents.

[0082] The desired processing viscosity is set in general by addingsolvent or water. In order to set specific processing viscosities or toobtain particular Theological properties it is also possible to usethickeners or combinations of different thickeners, such as ionic andassociative thickeners.

[0083] Examples of suitable substrates are mineral building materialsurfaces, road coverings, wood and wood-based materials, metallicsurfaces, plastics, glass, textiles, fabric or paper.

[0084] The coating materials comprising the polyesterpolyols of theinvention are used as one-component (1K) or also as two-component (2K)coating materials.

[0085] The coating materials comprising the polyesterpolyols of theinvention are used preferably as primers, surfacers, pigmented topcoatmaterials and clearcoat materials in the field of automotive refinishand large-vehicle finishing, in general industrial coating, in thecoating of plastics and also in wood coating. Particular preference isgiven to use for applications which call for particularly highapplication safety, rapid drying, a rapid increase in hardness to a highultimate hardness but with good elasticity, very good opticalproperties, characterized by very good levelling and high gloss, andalso good resistance to solvents, chemicals, water and weathering, suchas, for example, in automotive refinish and large-vehicle finishing orin general industrial coating.

[0086] The coating compositions comprising the polyesterpolyols of theinvention can be applied to the respective substrates by any of a verywide variety of spraying techniques, such as air-pressure spraying,airless spraying or electrostatic spraying techniques, usingone-component or two-component spraying units, or else by brushing,rolling, flowcoating or knifecoating.

[0087] The coatings are dried and cured in general under normaltemperature conditions, i.e. without heating of the coating. However, itis also possible to use the coating compositions of the invention toproduce coatings which following application are dried and cured atelevated temperature, e.g. at 40 to 250° C., preferably at 40 to 150° C.and more preferably at 40 to 100° C.

[0088] The polyesterpolyols of the invention with cyclic imide groupslead to improved properties in the coatings produced from them.Solvent-containing and aqueous two-component polyurethane coatingmaterials comprising the polyesterpolyols of the invention give coatingsfeaturing very rapid drying, high hardness coupled with good elasticity,high resistance to solvents, chemicals and water, very good levelling,and also very high gloss. Aqueous dispersions based on thepolyesterpolyols of the invention feature better storage stability thanthe polyester dispersions of the prior art, even at elevatedtemperatures of 40 to 50° C., and a better hydrolysis resistance.

EXAMPLES

[0089] In the examples below all percentages are by weight.

[0090] The stated “solids content” was determined by the thick-layermethod, in which a defined amount of sample is dried in a convectionoven at 125° C. for 1 h and the solids content is calculated from theresultant decrease in weight (based on EN ISO 3251).

[0091] The acid number (mg KOH/g sample) was determined by titrationwith 0.1 mol/l NaOH solution on the basis of DIN 53402.

[0092] The OH number (mg KOH/g sample) was determined by acetylation,hydrolysis and subsequent titration of the liberated HCl with 0.1 mol/lNaOH on the basis of DIN 53240.

[0093] Unless indicated otherwise the viscosities were determined at 23°C. on a VT 550 rotational viscometer from Haake GmbH, Karlsruhe, DE.

[0094] The statement “as-supplied form” refers to the as-is solution ordispersion of the polyesterpolyols; by “resin solids” is meant thenon-volatile resin fraction of the solution or dispersion present.

Example 1

[0095] Preparation of a Water-dilutable Polyesterpolyol I

[0096] 334 g of neopentylglycol, 638 g of 1,4-cyclohexanedimethanol, 733g of trimellitic anhydride and 432 g of ε-caprolactam were weighed outtogether into a reactor equipped with stirrer, heating, automatictemperature control, nitrogen inlet, column, water separator andreceiver and, with stirring and passing of nitrogen through the system,were heated to 230° C. in such a way that the overhead temperature ofthe column did not exceed 103° C. During this procedure the water ofreaction was separated off. Condensation was carried out to an acidnumber of <5 mg KOH/g.

[0097] The system was then cooled to 150° C. and 870 g ofneopentylglycol, 827 g of trimethylolpropane and 1874 g of phthalicanhydride were added. Subsequently, with stirring and passing ofnitrogen through the system, the reaction mixture was heated to 220° C.in such a way that the overhead temperature of the column did not exceed103° C. During this procedure, water of reaction continued to separateout. After the end of distillation, the water separator was replaced bya distillation bridge and the reaction mixture was stirred at 220° C.until the overhead temperature of the column fell to below 90° C. Thecolumn was removed and the reaction mixture was condensed with anincreased nitrogen flow to an acid number of <5 mg KOH/g. The system wasthen cooled to 140° C., 418 g of trimellitic anhydride were added andthe mixture was stirred at 170° C. until an acid number of about 35 mgKOH/g was reached. Up to this point in the preparation of the polyestera total of about 1770 g of polyester resin had been removed as a resultof sampling and other removals. The remaining mixture was then cooled to130° C., and 210 g of dipropylene glycol dimethyl ether were added anddissolved in at 100° C. over one hour. The resulting solution was thenstirred at 50° C. into a mixture of 134 g of N,N-dimethyl-ethanolamineand 3174 g of deionized water, which was at 50° C., over the course ofone hour. The resulting product was adjusted with further water to asolids content of about 47% by weight. This gave an opaque dispersionwith a bluish shimmer which had a solids content of 46.7% by weight interms of polyesterpolyol (measured as the non-volatile fraction of adispersion sample which was dried in a forced-air oven at 125° C. for 60minutes), an acid number of 16.3 mg KOH/g (based on as-supplied form),an OH number of 116 mg KOH/g (based on resin solids) and a viscosity of2306 mPa·s at 23° C. The dispersion contained about 2.4% by weight ofdipropylene glycol dimethyl ether, about 1.7% by weight ofN,N-dimethylethanolamine and about 49.2% by weight of water. The productcan be diluted further with water and is suitable for use in aqueoustwo-component polyurethane coating materials.

Example 2

[0098] Preparation of a Water-dilutable Polyesterpolyol II

[0099] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 1204 g ofneopentyl glycol, 638 g of 1,4-cyclohexanedimethanol, 1111 g oftrimellitic anhydride, 432 g of ε-caprolactam, 827 g oftrimethylolpropane, 1874 g of phthalic anhydride, 210 g of dipropyleneglycol dimethyl ether and 120 g of N,N-dimethylethanolamine. Theresulting product was adjusted with water to a solids content of about43% by weight. This gave an opaque dispersion with a bluish shimmerwhich had a solids content of 42.7% by weight in terms ofpolyesterpolyol (measured as the non-volatile fraction of a dispersionsample which was dried in a forced-air oven at 125° C. for 60 minutes),an acid number of 13.1 mg KOH/g (based on as-supplied form), an OHnumber of 117 mg KOH/g (based on resin solids) and a viscosity of 410mpa·s at 23° C. The dispersion contained about 2.3% by weight ofdipropylene glycol dimethyl ether, about 1.3% by weight ofN,N-dimethylethanolamine and about 53.4% by weight of water. The productcan be diluted further with water and is suitable for use in aqueoustwo-component polyurethane coating materials.

Example 3

[0100] Preparation of a Water-dilutable Polyesterpolyol III

[0101] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 1197 g ofneopentylglycol, 590 g of 1,4-cyclohexanedimethanol, 1438 g oftrimellitic anhydride, 601 g of ε-caprolactam, 792 g oftrimethylolpropane, 1571 g of phthalic anhydride, 210 g of dipropyleneglycol dimethyl ether and 134 g of N,N-dimethylethanolamine. Theresulting product was adjusted with water to a solids content of about45% by weight. This gave an opaque dispersion with a bluish shimmerwhich had a solids content of 44.9% by weight in terms ofpolyesterpolyol (measured as the non-volatile fraction of a dispersionsample which was dried in a forced-air oven at 125° C. for 60 minutes),an acid number of 15.7 mg KOH/g (based on as-supplied form), an OHnumber of 109 mg KOH/g (based on resin solids) and a viscosity of 404mpa·s at 23° C. The dispersion contained about 2.4% by weight ofdipropylene glycol dimethyl ether, about 1.6% by weight ofN,N-dimethylethanolamine and about 51.0% by weight of water. The productcan be diluted further with water and is suitable for use in aqueoustwo-component polyurethane coating materials.

Example 4

[0102] Preparation of a Water-dilutable Polyesterpolyol IV

[0103] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 1139 g ofneopentylglycol, 533 g of 1,4-cyclohexanedimethanol, 1646 g oftrimellitic anhydride, 723 g of ε-caprolactam, 760 g oftrimethylolpropane, 1292 g of phthalic anhydride, 210 g of dipropyleneglycol dimethyl ether and 137 g of N,N-dimethylethanolamine. Theresulting product was adjusted with water to a solids content of about37% by weight. This gave an opaque dispersion with a bluish shimmerwhich had a solids content of 36.8% by weight in terms ofpolyesterpolyol (measured as the non-volatile fraction of a dispersionsample which was dried in a forced-air oven at 125° C. for 60 minutes),an acid number of 13.4 mg KOH/g (based on as-supplied form), an OHnumber of 98 mg KOH/g (based on resin solids) and a viscosity of 842mPa·s at 23° C. The dispersion contained about 1.9% by weight ofdipropylene glycol dimethyl ether, about 1.3% by weight ofN,N-dimethylethanolamine and about 59.8% by weight of water. The productcan be diluted further with water and is suitable for use in aqueoustwo-component polyurethane coating materials.

Example 5

[0104] Preparation of a Water-dilutable Polyesterpolyol V

[0105] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 1137 g ofneopentylglycol, 533 g of 1,4-cyclohexanedimethanol, 1646 g oftrimellitic anhydride, 723 g of ε-caprolactam, 753 g oftrimethylolpropane, 1330 g of hexahydrophthalic anhydride, 210 g ofdipropylene glycol dimethyl ether and 137 g of N,N-dimethylethanolamine.The resulting product was adjusted with water to a solids content ofabout 37% by weight. This gave an opaque dispersion with a bluishshimmer which had a solids content of 36.7% by weight in terms ofpolyesterpolyol (measured as the non-volatile fraction of a dispersionsample which was dried in a forced-air oven at 125° C. for 60 minutes),an acid number of 12.8 mg KOH/g (based on as-supplied form), an OHnumber of 99 mg KOH/g (based on resin solids) and a viscosity of 5345mPa·s at 23° C. The dispersion contained about 1.9% by weight ofdipropylene glycol dimethyl ether, about 1.3% by weight ofN,N-dimethylethanolamine and about 59.8% by weight of water. The productcan be diluted further with water and is suitable for use in aqueoustwo-component polyurethane coating materials.

Example 6

[0106] Preparation of a Water-dilutable Polyesterpolyol VI

[0107] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 920 g oftrimellitic anhydride, 337 g of ε-caprolactam, 2056 g oftrimethylolpropane, 858 g of hexahydrophthalic anhydride, 463 g ofisophthalic acid, 1284 g of 2-ethylhexanoic acid, 210 g ofN-methylpyrrolidone and 157 g of N,N-dimethylethanolamine. The resultingproduct was adjusted with water to a solids content of about 45% byweight. This gave an opaque dispersion with a bluish shimmer which had asolids content of 45.0% by weight in terms of polyesterpolyol (measuredas the non-volatile fraction of a dispersion sample which was dried in aforced-air oven at 125° C. for 60 minutes), an acid number of 19.1 mgKOH/g (based on as-supplied form), an OH number of 112 mg KOH/g (basedon resin solids) and a viscosity of 2075 mPa·s at 23° C. The dispersioncontains about 2.4% by weight of N-methylpyrrolidone, about 1.8% byweight of N,N-dimethylethanolamine and about 50.8% by weight of water.The product can be diluted further with water and is suitable for use inaqueous two-component polyurethane coating materials.

Example 7

[0108] Preparation of a Water-dilutable Polyesterpolyol VII

[0109] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 1349 g oftrimellitic anhydride, 590 g of ε-caprolactam, 1896 g oftrimethylolpropane, 383 g of hexahydrophthalic anhydride, 413 g ofisophthalic acid, 1284 g of 2-ethylhexanoic acid, 210 g ofN-methylpyrrolidone and 155 g of N,N-dimethylethanolamine. The resultingproduct was adjusted with water to a solids content of about 48% byweight. This gave an opaque dispersion with a bluish shimmer which had asolids content of 47.9% by weight in terms of polyesterpolyol (measuredas the non-volatile fraction of a dispersion sample which was dried in aforced-air oven at 125° C. for 60 minutes), an acid number of 19.4 mgKOH/g (based on as-supplied form), an OH number of 100 mg KOH/g (basedon resin solids) and a viscosity of 2536 mpa·s at 23° C. The dispersioncontained about 2.5% by weight of N-methylpyrrolidone, about 2.0% byweight of N,N-dimethylethanolamine and about 47.5% by weight of water.The product can be diluted further with water and is suitable for use inaqueous two-component polyurethane coating materials.

Example 8

[0110] Preparation of a Solvent-containing Polyesterpolyol VIII

[0111] 1857 g of trimethylolpropane, 1573 g of1,4-cyclohexanedicarboxylic acid, 1174 g of hexahydrophthalic anhydrideand 862 g of ε-caprolactam were weighed out together into a reactor asin example 1 and, with stirring and passage of nitrogen through thesystem, were heated to 220° C. in such a way that the overheadtemperature of the column did not exceed 103° C. During this procedure,water of reaction separated out. After the end of distillation, thewater separator is replaced by a distillation bridge and the reactionmixture is stirred at 220° C. until the overhead temperature of thecolumn fell to below 90° C. The column was removed and the reactionmixture was condensed with an increased nitrogen flow to an acid numberof <3.5 mg KOH/g. The system was then cooled to 120° C. 254 g ofhexahydrophthalic anhydride and 1250 g of butyl acetate were added andthe mixture was stirred at 120° C. until an acid number of about 22 mgKOH/g was reached. The resulting solution was then cooled to 50° C. andfiltered through a filter (Seitz T 5500). This gave a clear,light-colored polyester solution having a solids content of 76.2% byweight, a viscosity at 23° C. of 6950 mPas, an OH number of 99 mg KOH/gand an acid number of 22.2 mg KOH/g.

Example 9, Comparative

[0112] Preparation of a Water-dilutable Polyesterpolyol IX

[0113] Polyesterpolyol prepared in analogy to example 1, but trimelliticanhydride and ε-caprolactam from the first condensation step had beenreplaced by isophthalic acid.

[0114] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 1286 g ofneopentyl glycol, 574 g of 1,4-cyclohexanedimethanol, 846 g oftrimethylolpropane, 586 g of isophthalic acid, 2089 g of phthalicanhydride, 418 g of trimellitic anhydride, 210 g of dipropylene glycoldimethyl ether and 123 g of N,N-dimethylethanolamine. The resultingproduct was adjusted with water to a solids content of about 41% byweight. This gave an opaque dispersion with a bluish shimmer which had asolids content of 40.5% by weight in terms of polyesterpolyol (measuredas the non-volatile fraction of a dispersion sample which was dried in aforced-air oven at 125° C. for 60 minutes), an acid number of 13.8 mgKOH/g (based on as-supplied form), an OH number of 115 mg KOH/g (basedon resin solids) and a viscosity of 442 mPa·s at 23° C. The dispersioncontained about 2.2% by weight of dipropylene glycol dimethyl ether,about 1.3% by weight of N,N-dimethylethanolamine and about 55.5% byweight of water. The product can be diluted further with water and issuitable for use in aqueous two-component polyurethane coatingmaterials.

Example 10, Comparative

[0115] Preparation of a Water-dilutable Polyesterpolyol X

[0116] Polyesterpolyol prepared in analogy to example 7, but trimelliticanhydride and ε-caprolactam had been replaced by isophthalic acid andhexahydrophthalic anhydride in the first condensation step.

[0117] In analogy to example 1 a water-dilutable polyesterpolyol or anaqueous polyester was prepared from the following components: 2184 g oftrimethylolpropane, 957 g of hexahydrophthalic anhydride, 1032 g ofisophthalic acid, 1272 g of 2-ethyl-hexanoic acid, 355 g of trimelliticanhydride, 215 g of N-methylpyrrolidone and 157 g ofN,N-dimethylethanolamine. The resulting product was adjusted with waterto a solids content of about 45% by weight. This gave an opaquedispersion with a bluish shimmer which had a solids content of 44.0% byweight in terms of polyesterpolyol (measured as the non-volatilefraction of a dispersion sample which was dried in a forced-air oven at125° C. for 60 minutes), an acid number of 16.7 mg KOH/g (based onas-supplied form), an OH number of 130 mg KOH/g (based on resin solids)and a viscosity of 210 mPa·s at 23° C. The dispersion contains about2.4% by weight of N-methylpyrrolidone, about 1.8% by weight ofN,N-dimethylethanolamine and about 50.8% by weight of water. The productcan be diluted further with water and is suitable for use in aqueoustwo-component polyurethane coating materials.

Application Examples

[0118] In the following application examples conventional methods ofcoatings technology were used to prepare pigmented two-componentpolyurethane paints for different fields of use and these paints wereapplied to metal test panels under standard conditions and cured. Inaddition to the specific paint properties for the individualapplications, such as solvent and chemical resistance, film hardness andflexibility, for example, the principal parameters assessed were thedrying rate of the paints, the levelling and gloss of the films, and thewater resistance. Products employed: Surfynol ® 104 E: Defoaming wettingagent, air products, sold by W. Biesterfeld & Co., Hamburg, DE Tronox ®R-KB-4: Titanium dioxide pigment, Kerr McGee Pigments GmbH & Co. KG, DEAcrysol ® RM 8: 20% strength in ethanol, thickener, Rohm & HaasDeutschland GmbH, Frankfurt/Main, DE Byk ® 346 Levellingadditive/substrate wetting, Byk Chemie, Wesel, DE Byk ® 380 Levellingadditive/anticrater agent, Byk Chemie, Wesel, DE Bayhydur ® VP LS 2319Hydrophilicized aliphatic polyisocyanate, Bayer AG Leverkusen, DESurfynol ® 104 BC: Defoaming wetting agent, air products, sold by W.Biesterfeld & Co., Hamburg, DE Baysilone ® VP AI 3468 10% strength inbutylglycol, slip additive, Borchers GmbH, Monheim, DE Borchigen ® SN 95Wetting agent and dispersant, Borchers GmbH, Monheim, DE Borchigel ® PW25 Thickener, Borchers GmbH, Monheim, DE

Example 11

[0119] White two-component topcoat material for general industrialcoating, based on the polyesterpolyol of example 1.

[0120] Component 1

[0121] In a commercially customary dissolver (15 minutes at a peripheralspeed of 10 m/s) a millbase was prepared to the following formulation:

[0122] 33.00 parts by weight polyesterpolyol I

[0123] 0.81 part by weight Surfynol® 104 E

[0124] 30.12 parts by weight titanium dioxide Tronox® R-KB-4

[0125] 3.13 parts by weight deionized water

[0126] The millbase was dispersed in a Skandex shaker with Siliquartzbeads of 2 mm in diameter for about 60 minutes. The millbase was thenseparated from the glass beads by sieving and, with stirring, thefollowing paint components were added (make-up):

[0127] 12.20 parts by weight polyesterpolyol I (from example 1)

[0128] 0.55 part by weight Acrysol® RM 8, 20% strength in ethanol,

[0129] 0.21 part by weight Byk® 346

[0130] 0.32 part by weight Byk® 380

[0131] Thereafter component 1 (formulated polyol component) was readyfor further use. To produce a two-component paint component 1 was mixedwith the polyisocyanate curing agent (component 2). Component 2 containsfrom the following ingredients:

[0132] Component 2

[0133] 15.73 parts by weight Bayhydur® VP LS 2319

[0134] 3.93 parts by weight methoxypropyl acetate

[0135] 100.00 parts by weight

[0136] Components 1 and 2 were mixed at a stirrer speed of 2000 rpm for2 minutes. The finished two-component paint was then adjusted to a sprayviscosity of about 30 s (efflux time from DIN 4 mm cup at 23° C.) byadding water. The white paint thus formulated was applied using acommercially customary spray gun (Sata Jet B, nozzle 1.4 mm, pressure3.5 to 4 bar) to metal test panels [steel: 20×10 cm, aluminium: 15×7 cm,zinc: 16.5×6.5 cm and Unibond WH/60/OC (iron-phosphated steel): 20×10cm] and subjected to paint testing after 1 day, 7 days and 14 days ofdrying at room temperature (23° C., 50% relative atmospheric humidity).

[0137] Using a doctor blade (120 μm slot width) the paint was applied toglass plates and, with drying at room temperature, the initial drying,evaporation time and gloss were measured. The potlife (doubling in sprayviscosity) was determined by measuring the efflux time (DIN 4 mm cup at23° C.). The initial drying was determined in accordance with DIN 53150. The following technical paint properties were tested on the curedcoatings: Glass plates/steel: Determination of gloss (20°/60°) inaccordance with DIN 67 530 Glass plates: Determination of evaporationtime in accordance with DIN 53 157 Steel/aluminium/zinc panel: Testingof adhesion in accordance with EN ISO 2409 Steel panel: Testing ofErichsen cupping in accordance with DIN ISO 1520 Steel panel: Testing ofchemical resistance (acetone/ xylene, 1 min/5 min exposure) UnibondWH/60/OC: Testing of water resistance after 16 hours of drying at roomtemperature. Gloss: in accordance with DIN 67 530 Blistering: inaccordance with DIN 53 209 Adhesion: in accordance with EN ISO 2409

Example 12

[0138] White two-component topcoat material for large-vehicle finishing,based on the polyesterpolyol I.

[0139] Component 1

[0140] In a commercially customary dissolver (15 minutes at a peripheralspeed of 10 m/s) a millbase was prepared to the following formulation:

[0141] 38.91 parts by weight polyesterpolyol I

[0142] 1.09 parts by weight Surfynol® 104 BC

[0143] 0.91 part by weight Baysilone® VP AI 3468, 10% strength inbutylglycol

[0144] 6.98 parts by weight Borchigen® SN 95

[0145] 0.13 part by weight Borchigel® PW 25⁾

[0146] 29.02 parts by weight titanium dioxide Tronox® R-KB-4

[0147] The millbase was dispersed in a Skandex shaker with Siliquartzbeads of 2 mm in diameter for about 60 minutes. The millbase was thenseparated from the glass beads by sieving. Thereafter component 1(formulated polyol component) was ready for further use. To produce atwo-component paint component 1 was mixed with the polyisocyanate curingagent (component 2). Component 2 contained from the followingingredients:

[0148] Component 2 $\frac{\begin{matrix}{15.53\quad {parts}\quad {by}\quad {weight}\quad {Bayhydur}^{®}{VP}\quad {LS}\quad 2319} \\{3.88\quad {parts}\quad {by}\quad {weight}\quad {methoxybuty1}\quad {acetate}}\end{matrix}}{100.00\quad {parts}\quad {by}\quad {weight}}$

[0149] Components 1 and 2 were mixed at a stirrer speed of 2000 rpm for2 minutes. The finished two-component paint was then adjusted to a sprayviscosity of about 25 s (efflux time from DIN 4 mm cup at 23° C.) withdeionized water. The white paint thus formulated was applied in analogyto example 11 using a commercially customary spray gun of the type SataJet HVLP NR 2000 (1.3 mm nozzle, pressure 3.5 to 4 bar) from SataFarbspritztechnik GmbH, Komwestheim, DE to coated, circularly perforatedmetal panels, dimensions: 150×300 mm, available commercially underarticle No. 17542H11ME from Heinz Zanders, Liebigstraβe 22, 42719Solingen, DE. Curing was carried out at 60° C. for 30 minutes and thenat room temperature.

Examples 13 to 16

[0150] As in example 11, white two-component topcoat materials forgeneral industrial coating were prepared on the basis ofpolyesterpolyols II (example 2), III (example 3), IV (example 4) and V(example 5) and applied.

Examples 17 and 18

[0151] As in example 12, white two-component topcoat materials forlarge-vehicle finishing are prepared on the basis of polyesterpolyols VI(example 6) and VII (example 7) and applied.

Comparative Example 19

[0152] As in example 11, white two-component topcoat materials forgeneral industrial coating are prepared on the basis of polyesterpolyolIX and applied.

Comparative Example 20

[0153] As in example 12, white two-component topcoat materials forlarge-vehicle finishing are prepared on the basis of polyesterpolyol Xand applied.

[0154] Test Results of Aqueous Two-component Polyurethane Paints Basedon the Polyesterpolyols I to V and IX (General Industrial Coating):TABLE 1 Results of the technical paint tests Paint from Example No. 1113 14 15 16 19 Potlife, h 6 5 5 5 5 6 Drying, T1/T3 in h 1/5 0.5/5  0.5/5     1/5.5   1/5.5 1.5/5.5 Pendulum damping, s after  1 d 113 95101 85 82 110  7 d 129 102 110 99 93 115 14 d 130 104 113 103 97 118Erichsen extension, mm after 14 d 10.0 8.6 8.0 9.3 9.4 7.4 Gloss 20°/60°88/96 88/96 88/96 87/97 86/94 89/96 Resistance¹⁾ to xylene/acetone  1 d2/2 1/2 1/2 1/2 1/2 2/2 5 min exposure time  7 d 1/2 0/2 0/2 1/2 0/2 1/214 d 1/2 0/2 0/2 0/2 0/2 1/2 Resistance²⁾ to water after  1 d 74/9576/93 79/94 72/95 69/91 70/93  7 d 73/92 73/89 75/90 68/87 65/84 11/2814 d 53/83 51/76 53/79 49/72 48/70 — Adhesion¹⁾ to steel after  1 d 2 11 1 0 2  7 d 2 1 1 0 0 2 14 d 2 1 1 1 1 1 Adhesion¹⁾ to zinc after  1 d2 1 1 1 1 1  7 d 2 1 1 1 0 2 14 d 2 1 1 1 1 1 Adhesion¹⁾ to A1 after  1d 2 1 1 1 1 2  7 d 2 1 1 1 1 2 14 d 2 1 1 1 1 2 Adhesion¹⁾ to Unibond  1d 2 1 1 1 1 2  7 d 2 2 2 2 2 5 14 d 2 3 2 3 3 —

[0155] Test Results of Aqueous Two-component Polyurethane Paints Basedon the Polyesterpolyols I, VI, VII and X (Large-vehicle Finishing):TABLE 2 Results of the technical paint tests Paint from Example No. 1217 18 20 Potlife, h 6 6 6 6 Drying, T1/T3 in h 2/6 2.5/6 2/6 3/8Pendulum damping, s after 1 d 126 64 120 73 4 d 176 116 154 94 7 d 175116 161 98 Erichsen extension, mm after 14 d  10.0 10.0 10.0 10.0 Gloss20° 96 90 88 87 Haze 20 22 25 35 Resistance¹⁾ to xylene 1 d 1 2 2 2 5min after 4 d 1 1 1 2 7 d 1 1 1 1 Resistance¹⁾ to MPA 1 d 1 2 2 2 5 minexposure time after 4 d 1 2 1 2 7 d 1 1 1 1 Resistance¹⁾ to premium- 1 d1 1 2 2 grade petrol 4 d 1 1 1 2 5 min exposure time after 7 d 1 1 1 1Resistance¹⁾ to water 1 d 1 2 2 3 1 h exposure time after 4 d 1 1 1 3 7d 1 1 1 2

[0156] Discussion of the Test Results:

[0157] With the polyesterpolyols of examples 1 to 7, 9 and 10 it ispossible in combination with water-dilutable aliphatic polyisocyanatesto prepare aqueous two-component polyurethane paints which possess asufficiently long processing time, dry rapidly on application to asubstrate, and give glossy to highly glossy paint films. The paintsbased on the polyesters I to VII of the invention all have more rapiddrying, greater hardness and better solvent resistance than the paintsbased on the comparative polyesters IX and X. Of critical significance,however, is the substantially better water resistance of the paint filmsbased on the polyesters of the invention in comparison to the paintsbased on the comparative polyesters.

1. Polyesterpolyols which comprise structural units of the generalformula (I)

and/or which comprise structural units of the general formula (II)


2. Polyesterpolyols which, as end groups, comprise structural units ofthe general formula (III)

and/or comprise structural units of the general formula (IV)

in which R¹ and R², independently of one another, are identical ordifferent and stand for hydrogen, halogen, unsubstituted or substitutedC₁-C₁₈ alkyl, C₂-C₁₈ alkenyl, C₂-C₁₈ alkynyl, C₃-C₁₂ cycloalkyl, C₃-C₁₂heterocycloalkyl, C₆-C₂₄ aryl, C₁-C₁₈ alkoxy, C₁-C₁₈ alkylthio, C₁-C₁₈alkylamino radicals or with the joining carbon atom of the C₄Nfive-membered ring form a C₃-C₁₂ cycloalkyl or C₂-C₁₃ heterocycloalkylradical optionally containing oxygen, nitrogen and/or sulphur or bothtogether with the joining carbon atoms of the C₄N five-membered ringform a fused cyclic or polycyclic ring system which is saturated,unsaturated, partly or fully aromatic, is optionally substituted andoptionally contains oxygen, nitrogen and/or sulphur.
 3. Polyesterpolyolsaccording to claim 1 or 2, characterized in that the polyesterpolyolscontain free hydroxyl groups and carboxyl groups.
 4. Polyesterpolyolsaccording to claim 1 or 2, characterized in that the hydroxyl number isfrom 10 to 400 mg KOH/g.
 5. Polyesterpolyols according to claim 1 or 2,characterized in that the acid number is from 5 to 100 mg KOH/g. 6.Process for preparing the polyesterpolyols according to claim 1 by (I)reacting an anhydride of trimellitic acid and/or of pyromellitic acidwith a cyclic lactam (B), (II) synthesizing a hydroxy-functionalpolyester by adding an alcohol component (C) containing one or morealiphatic or cycloaliphatic C₃-C₁₀ polyols having a functionality ofmore than 2 (C1) and/or one or more aliphatic or cycloaliphatic C₂-C18diols (C2) and optionally one or more aliphatic, cycloaliphatic oraraliphatic monofunctional C₁-C18 alcohols (C3), and also optionallyadding an acid component (A) comprising one or more difunctionalcarboxylic acids or their anhydrides (A1) and/or one or morepolyfunctional carboxylic acids or their anhydrides (A2) and optionallyone or more monocarboxylic acids (A3).
 7. Process for preparing thepolyesterpolyols according to claim 2 by (I) reacting an anhydride of adifunctional carboxylic acids (A1) with a cyclic lactam (B), (II)synthesizing a hydroxy-functional polyester by adding an alcoholcomponent (C) containing one or more aliphatic or cycloaliphatic C₃-C₁₀polyols having a functionality of more than 2 (C1) and/or one or morealiphatic or cycloaliphatic C₂-C₁₈ diols (C2) and optionally one or morealiphatic, cycloaliphatic or araliphatic monofunctional C₁-C₁₈ alcohols(C3), and also optionally by adding an acid component (A) comprising oneor more difunctional carboxylic acids or their anhydrides (A1) and/orone or more polyfunctional carboxylic acids or their anhydrides (A2) andoptionally one or more monocarboxylic acids (A3).
 8. Process accordingto claims 6 or 7, characterized in that in a third stage, thehydroxy-functional polyester from stage (II) is reacted with acarboxylic anhydride selected from the group of the difunctionalcarboxylic acids (A1) and/or trifunctional carboxylic acids (A2′), withring opening and half-ester formation.
 9. Solutions or dispersionscomprising polyesterpolyols according to claim 1 and/or
 2. 10. Coatingcompositions comprising polyesterpolyols according to claim 1 and/or 2.11. Coating compositions according to claim 10, characterized in thatthey are water-containing.
 12. Coating compositions according to claim10, characterized in that they are solvent-containing.
 13. Process forpreparing coating compositions according to claim 10, in which one ormore optionally blocked polyisocyanates, optionally further binders andauxiliaries and additives are stirred or emulsified into one or morepolyesterpolyols according to claim 1 and/or 2 or into solutions ordispersions according to claim
 9. 14. Use of coating compositionsaccording to claim 10 for coating and/or adhesively bonding substrates.15. Substrates coated with coating compositions according to claim 10.